boost surge above 0.45 bar

[paulr33]

Hi guys,

My car in the last two days has been surging when on boost. Ive only noticed it a bit on Wednesday night and a lot on Thursday. It boosts fine until it goes past 0.50 bar, once it goes past it sounds likes theres a surge in the air line somewhere and the boost controller detects overboost and cuts out. If I keep the throttle floored once past 0.50 bar i hear something like "vroom vroom vroom vroom" from the engine, which I suspect is because of the fluctating air pressure levels. The stcok guage and evc both show boost going to 0.67bar then 0.58 then 0.68 then 0.71 then 0.65 then it finally beeps overboost a few times and drops back to the minimum level of 0.45 bar and stays at that.

The guage also shows boost going to 0.70 bar and then up and down and up and down and up and down and finally halts at 0.45 when the evc custs out. At this level everything is fine and I dont get the surging problem (0.45). With the evc off I have the same results of 0.45 bar and no surge. With the EVC on and set to 0.50 bar it does surge a tiny tiny bit and boost seems ok. Is this compressor/turbo failure/bad stuff or is this the controller doing something wrong? I did an evc reset and tried to do its relearn but it wont relearn itself because the boost isnt stable, I reset it do stage 3 then 2 then 1 when Im usually on stage 1 it defaults back to 3. I get the surging a little bit when im doing the self learning, a lot in stage 1 so it just resets it self and I can't complete the learn. The boost does increase a bit between stage 3 and 1 and I can see and feel it but the surge comes with it. Here's what else ive noticed

Airflow signal is stable

Injector signal is OK and not 100% ing or anything

Knock is minimal and doesnt go nuts when I feel and see the surge

Happens on nights and days so I guess is not intake related?

Running the EVC in manual mode at 0.52 bar causes surge as well

No engine warning lights come on from power fc

Car config:

rb25det series II with 120,000

power fc

hks evc3

3" dump and front pipe with 3" exhaust

hybrid or some brand fmic

pod filter with heat shield (although its dodgy)

Now I can't debug it at all with the evc anymore as its stuck in learn mode

Anyone have any ideas or sugestions? I've had a visual check of the all the presure lines to the solenoid and they seem OK and nothing appears loose. This config for the car hasnt changed in a few months and I've had the evc stable and working well for about 5 months now. Anyone have a spare evc3 soleloid?

Thanks

[paulr33]

I managed to the evc working again after about 7shots at the relearn stage. Now at 0.39 bar Its fine and no surging or "woom woom woom" when on boost. If i set the EVC to 0.49ish 0.52ish then i get surging "woom woom woom woom" through the rev range. At 0.70bar it just gets louder and worse. I still have plently power and and all the usual stuff happens (until the evc does its overboost protection). Im able to feel, see and hear the surgging. I can hear it from the engine, I can see it on the guages (stock boost and evc digital value) and I can feel it (power from car backs on and off with the boost fluctuating)

[paulr33]

I managed to the evc working again after about 7shots at the relearn stage. Now at 0.39 bar Its fine and no surging or "woom woom woom" when on boost. If i set the EVC to 0.49ish 0.52ish then i get surging "woom woom woom woom" through the rev range. At 0.70bar it just gets louder and worse. I still have plently power and and all the usual stuff happens (until the evc does its overboost protection). Im able to feel, see and hear the surgging. I can hear it from the engine, I can see it on the guages (stock boost and evc digital value) and I can feel it (power from car backs on and off with the boost fluctuating)

Anyone have any ideas? I dont have smoke or bearing noises or loss of boost.

[Trust33]

surging.I have a leaking intercooler hose and i think that it is my cause of overboost.1 hose has a crack in it and the others are very old.I think it's time for a revamp.

[paulr33]

after some more testing it seems my original diagnosis was incorrect. if i watch the afm value on the hand controller when i get the problem the afm value does squiggles as its going through the rev range, the squiggles conincide with the "surging". could be a dead afm? ive cheked the plug and all seems ok will pull apart and have a looksy. anyone have a spare r33 afm i can borrow to test with? or a z32 (ill buy it) to try. or a spare evc3 solenoid in case back to the other theory that the solenoid is angry about something

[paulr33]

ok after some testing at chasers it seems the crank angle sensor is ****ed and under heavy load it ****s up the timing, which gives it the jerky/surging feeling. the timing on the hand controller when you monitor it seems fine and starts to advance under throttle then when its gets near 3500ish the timing goes spastic and you get the jerky feeling. gonna get the cas changed and see how that goes

[Trust33]

Keep us updated.

[paulr33]

anyone know if an r32 rb20 crank angle sensor will fit and work OK?

[GTR-Ben]

I would like an answer to this also.. I have a feeling it's an EVC problem though and not an engine problem.

We have the exact same thing happening.. EVC III on a SR20DET engine. Controller off it's fine. With it on, it does the surging thing as you described.. but it doesn't always do it, and we can't seem to see what causes it to start except being completely random.

It is a really annoying problem.. I have never had it happen before and I have used quite a few HKS Boost Controllers.

[paulr33]

will let you know

[paulr33]

Hey guys,

Tonight just after I finished work drove my car home and had some interesting results:

Start car, all seems ok. Boost controller is off (green display) and its running boost from the actuator which is about 0.40 bar ish. Car drives fine no problems whatsoever. Watch the timing on the hand controller all seems fine. Car is almost at full operating temp (about 50 odd) and I turn on the boost controller (goes red) and I get the timing spastic problem. Fair enough. Back off on the throttle and let it warm up completely. Try again, same problem spastic timing and surging. Leave the boost controller on, drive a bit more but not going on boost too much as I didnt want to cause any damage etc. Go through a few sets of lights, give it a bit of stick in 2nd gear cranks up to 0.80 bar and no surge/spastic timing. Hand controller shows 22deg timing, boost shows 0.80 bar and throttle is nailed.

All good and my power and boost is back. Try a few more times and its sweet. Turn the car off and back on again. (Reboot). Try again boost is the same and power is back, no more surge and timing is dead on 22deg under heavy load. Turn off car again after a few more runs and try again. All working fine. Go over a medium bump next to some tram tracks, nail the throttle spastic timing and surging comes back. Try a few more times, same problem. Turn car off and on again. Spastic timing and surge. Hit the evc controller unit. Nail the throttle problem solved. It seems the EVC unit is a bit loose or dodgy and when it gets bumped it dies or goes into a strange mod and just has a fit. I suspect the wires could be a bit loose. Over and over I was able to replicate the problem just by tapping the EVC unit when the problem came back. WIll pull the unit apart (mate at work is an electronics guru) and check it out, could be a loose bit inside or a wire terminal. Glad its all sorted and didnt change the crank angle sensor. Thanks for help and listening

[RB30-POWER]

Could be a cracked/broken solder joint inside the unit or dodgy wiring job.

[GTR-Ben]

Thats what I though.. it has to be an electrical problem they way it's off an on.. and also has to be the control unit.

Hope it's something that can be fixed easily.. strange that you get the exact same problem..

[paulr33]

Hi Ben (and anyone else who has seen this problem) sorry to dig up the old thread. I haven't had this problem occur since my first encounters of the issue and ****ing around with my airbox setup. Since then the valve body hasn't been mounted against the chassis. It's been cable tied in mid air so its not grounding itself. Since then no problems. I wonder if grounding the unit's valve body causes this problem on bad grounded cars?